When I just want to eat some kilometers but no altitude I cycle around Lake Zurich. Zürich - Rapperswil - Zürich is about 67 km and if you do it clockwise, there are only a few traffic lights. There is a tarred bicycle lane, only in Zürich you'll have to be considerate of pedestrians sometimes. During weekends, there is more car traffic during weekends. There are tours with better views but hey, nothing against Lake Zurich!
Western Zürich (Tram stop Triemli) - Waldegg - Sellenbüren - Stallikon - Türlen is a route with ca. 250m altitude difference. Without hurry it's 60 minutes (respectively 50 minutes back to Zürich). In Türlen you have the opportunity to take a swim in the lake, or wander around the lake in a preserve area (no bicycling allowed) or to go to a restaurant, so it's a reasonable destination. 75% with bicycle lane and a few tight curves.
Here are some suggestions for Zug, taken from Tourenguide.ch:
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For Switzerland there are very good maps available (13.50 Fr. if I remember correctly). I recommend the 1:50'000 ones for serious bicycling but there are also special bike maps available. In Zürich you can get them at
Orell Füssli, with explanation brochures for free. If you start your tour elsewhere, try the tourist center.
Happy biking!